Many attempts have been made to use various lipidic carriers to serve as a vehicle to transport molecules of interest.
For example EP 0848614 describes isolation and purification of endogenous microdomains or components of the mammalian cell membrane, including caveolae, and the potential use of these purified microdomains to deliver molecules, such as drugs, into various cells.
Another approach described in patent application PCT/IB2005/000204 describes bacterially derived minicells that are achromosomal products of E. coli or other bacterial cells, as a result of asymmetric cell division, that have intact cell walls. PCT/IB2005/000204 also describes the use of these minicells for delivery of drug molecules. The delivery may be targeted through the use of a bispecific ligand that has specificity for both the minicell surface structure and a cell surface receptor.
Li et al. (JBC, 1996, 271:45; 28647-54) describe expression of mammalian caveolin protein in insect cells and their assembly into caveolin-sized vesicles. However, these authors also describe how bacterial expression of caveolin protein fails to drive the formation of any morphological structures that resemble caveolae.
Murata and coworkers (PNAS, 1995, 92; 10339-43) describe the reconstitution of bacterially expressed caveolin into liposomes in a manner dependent upon at least one mole of exogenous cholesterol per mole of protein.
None of the above described systems permit reliable production, isolation and/or purification of a lipidic carrier with defined or consistent components. This may be due to the large degree of heterogeneity in eukaryotic vesicles.